wifi: mac80211: generate EMA beacons in AP mode

Add APIs to generate an array of beacons for an EMA AP (enhanced
multiple BSSID advertisements), each including a single MBSSID element.
EMA profile periodicity equals the count of elements.

- ieee80211_beacon_get_template_ema_list() - Generate and return all
EMA beacon templates. Drivers must call ieee80211_beacon_free_ema_list()
to free the memory. No change in the prototype for the existing API,
ieee80211_beacon_get_template(), which should be used for non-EMA AP.

- ieee80211_beacon_get_template_ema_index() - Generate a beacon which
includes the multiple BSSID element at the given index. Drivers can use
this function in a loop until NULL is returned which indicates end of
available MBSSID elements.

- ieee80211_beacon_free_ema_list() - free the memory allocated for the
list of EMA beacon templates.

Modify existing functions ieee80211_beacon_get_ap(),
ieee80211_get_mbssid_beacon_len() and ieee80211_beacon_add_mbssid()
to accept a new parameter for EMA index.

Signed-off-by: Aloka Dixit <quic_alokad@quicinc.com>
Co-developed-by: John Crispin <john@phrozen.org>
Signed-off-by: John Crispin <john@phrozen.org>
Link: https://lore.kernel.org/r/20221206005040.3177-2-quic_alokad@quicinc.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index c8c037a9e4e2..84d10e993eca 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1186,13 +1186,17 @@ ieee80211_vif_get_shift(struct ieee80211_vif *vif)
 }
 
 static inline int
-ieee80211_get_mbssid_beacon_len(struct cfg80211_mbssid_elems *elems)
+ieee80211_get_mbssid_beacon_len(struct cfg80211_mbssid_elems *elems, u8 i)
 {
-	int i, len = 0;
+	int len = 0;
 
-	if (!elems)
+	if (!elems || !elems->cnt || i > elems->cnt)
 		return 0;
 
+	if (i < elems->cnt)
+		return elems->elem[i].len;
+
+	/* i == elems->cnt, calculate total length of all MBSSID elements */
 	for (i = 0; i < elems->cnt; i++)
 		len += elems->elem[i].len;